The 'J. Edgar' star - who has previously dated Rachel McAdams, Salma Hayek, and Anne Hathaway - admitted it was a life threatening confrontation with a mountain lion in Big Sur, California, that convinced him his girlfriend, who he refused to name, is the woman for him.

Speaking on last night's (05.01.12) 'Tonight Show With Jay Leno', he said: "I knew (she was the one) on a kind of interesting trip that we took. I was doing this great movie in Big Sur, California and it was a very, very low budget movie. Often times they put you up in these terrible, little hotels and so they said you have $30 a day of a hotel allowance. And I used that money to find my own place to stay. And there's this guy who has an eco resort. We stayed there and had our first night. It was absolutely wonderful.

"The next day she stayed in the trailer, I hiked down and went to work. And we worked that day at this beautiful house in Big Sur and all over this house were signs that said, 'Beware of mountain lions.' What to do in case you see a mountain lion - all the noises you're supposed to make, clanging, yelling, make yourself as big as possible.

"That night, I then go home at 4 o'clock in the morning and I don't have a flashlight. And as I'm going up, I get to the point where I can see nothing, I am now going along hand by hand and I hear, totally serious, two big breaths, and six feet above me, I see the very slight glint of the eyes of a huge mountain (lion) and I literally proceed to do what I had just read in the instructions. And I started screaming and yelling and literally being as crazy as I could be. It padded off and just slowly went away and I worked my way into the trailer and I got in and I decided at that moment that this woman was the woman for me."